How to import .STL files into any CAE program?

[Spirits of Senna]

Sorry this thread is not a showcase of my own engineering project but rather it is asking a question. Not sure if this is the most appropriate to post under this forum. For the Forum Mods, please change the thread any where it may belong. My apologies in advance.

There is my problem.

Google SketchUp Warehouse has a long of completed car models to download for free. I would like to use CAE software such as Solidworks and Pro Engineer to have more precision in playing and shaping around the car models.

I can use Google SketchUp to export the files into .STL and .DWF. Unfortunately I have along of troubles importing the models as the two formates and play around them in the two listed CAE software. I can import the models but without any meshing done by the Solidworks or Pro Engineer, and cannot create features or shape right one the models, at least I don't know how.

I understand there are a lot of fine gentlemen and ladies, or course, that know how to get around this beside the obvious of drawing the model yourself from the grounds up in the CAE program.

Please help [-o<

Many thanks.

[Jersey Tom]

Admittedly it's been a while since I've done CAD, last version of SolidWorks I used is several years outdated at this point. But indeed once you export to a *.STL and bring that into say SolidWorks... as far as I'm aware, there's not much you can do - the geometry is more or less cast in stone and you can't do all the nice geometry modification you can in a parametric modeling package. Granted I could be wrong.

Pure speculation here but if you could export the model from its native format to a Parasolid and import that, maybe you could do some stuff with the geometry.

[Spirits of Senna]

I use the lastest Solidworks and there is this new feature where Solidworks attempts to make the .STL as a solid or facelets as illustrated here: https://grabcad.com/questions/tutorial- ... solidworks The result I get is still useless to me or it probably needs way more work than I can handle.

I have tried another method https://forum.solidworks.com/message/229516#229516 with MeshLab but Solidworks crashes out.

For Pro Engineer, it is like you said. The models are just stones once imported. They couldn't be build upon in my limited knowledge with the program.

[marcush.]

errm ...
you can import an STL file as a cloud of points .Catia allows this in V5 V19 in their digitised shape editor DSE ...basically you would then have to recreate the surfaces within Catia using quick surface reconstruction (QSR) tool ...then you have surface data which can be used .. mucho work .
It´s basically the same as you do when scanning a 3d surface-also stl data usually .

STL data format is used to feed into RP machinery .

Autodesk Alias does accept direct STL import -maybe this would be the easy way (or Rhino etc)


for ProE there is a plug in .

http://www.sycode.com/products/stl_impo ... import.pdf
http://www.sycode.com/products/index.htm


you can buy a seven days licence for around 30 $ there for some other Cad tools as well

[Jersey Tom]

Even if you can make a surface out of it, I'd say it's limited what you can probably do with it.

Bottom line is, once you export to a non-native (to SW) format like that... chances are you're boned. That's the reality of the situation. Yeah it's a pain in the rear, but that's how it is.

Not always a solution to everything...

[marcush.]

if you reconstruct the surface using the cad system ,as I suggested you have a shape that can be worked on and modified ,no question.
sure it is still a hull only with no real physical property ..but who said there was the magic key combination somewhere on your keyboard to solve all problems and get a fully engineered product without any effort...at least there is a way to generate a CAD reconstruction of the "standard tesselation language" file ...guys a STL file is nothing more than a surface wrap of triangles ...there is not more to derive from it than a surface.

[Spirits of Senna]

It seems like the reality is grim. I haven't tried it but it might work, not exactly sure. It is to extract cut areas of the .STL model that you want to play around with, then rebuild the cut-out parts in the CAE's CAD. Depending the size of the area, it might be advantageous to incorporate own work and imported model over redrawing the entire model.

Edit: It didn't work

Marcush have you tried the .STL importer yourself by any change? I believe they have another add-on for Solidworks too.

[lansdale]

I would like to use CAE software such as Solidworks and Pro Engineer to have more precision in playing and shaping around the car models.

As the main conversion expert and provider, I am asked this same question anywhere from 3 to 6 times every day since 1996. It is the #1 most mis-understood concept in the entire 3D graphics market. If you don't mind, let me chime in and provide a small snippet of the 5 page email I sent to each person every day.

You can't do this because SolidWorks and ProE are BREP solids modelers and SketchUp
just uses very simple polygon meshes. You can't turn meshes into a proper solids
model as you expect. It is like turning water back into an ice sculpture.

It's become an even more rampant problem since the SketchUp software became
popular back in 2010, as there's 25 million people all trying to use SketchUp
as a MCAD modeller (which it is not). I do explain this problem in a slightly deeper manner
online here:

http://www.okino.com/conv/exp_sketchup. ... nstruction

Most people on forums don't believe my comments but that is due to lack of understanding about mesh vs. NURBS/solids data. There is no magic to importing mesh data into SolidWorks or ProE, and all those cheap plug-ins from India just pull the wool over your eyes.

At most, you'll need one of the interactive surface approximation programs I would normally email someone directly.
They allow you to interactively re-surface a mesh model with NURBS
equivalents, after which you can then attempt to stitch the NURBS back into a
BREP solid. You do need a proper program to re-engineer the mesh data into
proper NURBS, and then turn the NURBS into solids.

Now, no one ends up doing this since the average costs are in the $5k range,
and you still need to spend many hours doing the reverse engineering yourself.

[Spirits of Senna]

Many thanks lansdale for explaining the issue.

I guess the effort in converting .STL files is labour intensive enough that it is better off drawing the model fresh in CAD.

[Lycoming]

That or try and find a model in a sldprt or prt format. Or, even IGES works, I think.

[gixxer_drew]

I don't know what you guys are smoking, I bring in full car bodies as STL files into SW all day and manipulate them six ways from Sunday. It's just a bit tricky working with facets instead of real SW geometry since an arc won't line up. What are you using this for? You will struggle with printing parts or machining molds or something.

The only problem is the 15,000 facets limit and that makes it nasty for a car level of complexity, but there are translation tools out there. Catia is probably probably what you want to be using.

[Jersey Tom]

I don't know what you guys are smoking, I bring in full car bodies as STL files into SW all day and manipulate them six ways from Sunday. It's just a bit tricky working with facets instead of real SW geometry since an arc won't line up.

That's the whole point.

[gixxer_drew]

I don't know what you guys are smoking, I bring in full car bodies as STL files into SW all day and manipulate them six ways from Sunday. It's just a bit tricky working with facets instead of real SW geometry since an arc won't line up.

That's the whole point.

Depends on the use like I was asking about, if it's not F1 and you are talking about CFD or mechanical modeling or something it's fine, just a bit mor trouble along the way. CFD you just need a mesh density less than the detail level of the model and she'll be right. There are tricks to smooth things out and blend them into your changes. Just takes time.

[Spirits of Senna]

That or try and find a model in a sldprt or prt format. Or, even IGES works, I think.

I have tried any IGES import to Solidworks yet but would I need to do a lot of post-import work in order to start shaping the model?

[Spirits of Senna]

I don't know what you guys are smoking, I bring in full car bodies as STL files into SW all day and manipulate them six ways from Sunday. It's just a bit tricky working with facets instead of real SW geometry since an arc won't line up. What are you using this for? You will struggle with printing parts or machining molds or something.

For CFD learning.

The only problem is the 15,000 facets limit and that makes it nasty for a car level of complexity, but there are translation tools out there. Catia is probably probably what you want to be using.

Can you elaborate further as to what I should do in CATIA with the STL to give me a start. I have learnt CATIA in school but just the basics. I just schools would teach meshing with 3D models than just simple model building and FEA simulation.